Cholenergic Drugs

Question 1

acetylcholinesterase

Answer 1

enzyme responsible for the immediate breakdown of acetylcholine when released from the nerve ending; prevents over-stimulation of cholinergic receptor sites

Question 2

Alzeheimer’s disease

Answer 2

degenerative disease of the cortex with loss of acetylcholine-producting cells and cholinergic receptors; characterized by progressive dementia

Question 3

cholinergic agonists

Answer 3

responding to acetylcholine; refers to receptor sites stimulated by acetylecholine, as well as neurons that release acetylcholine

Question 4

miosis

Answer 4

constriction of the pupil; relieves intraocular pressure in some types of glaucoma

Question 5

Myasthenia gravis

Answer 5

autoimmune disease characterized by antibodies to cholinergic receptor sites, leading to destruction of the receptor sites and decreased response at the neuromuscular junction; it is progressive and debilitating, leading to paralysis

Question 6

nerve gas

Answer 6

irreversible acetylcholinesterase inhibitor used in warfare to cause paralysis and death by prolonged muscle contraction and parasympathetic crisis

Question 7

parasympathomimetic

Answer 7

mimicking the effects of the parasympathetic nervous system, leading to bradycardia, hypotension, pupil constriction, increased GI secretions and activity, increase bladder tone, relaxation of sphincters, and bronchoconstriction

Question 8

bethanechol (Duvoid, Urecholine)- Prototype- Direct-Acting

Answer 8

PO/SQ. Treatment of nonobstructive postoperative and postpartum urinary retention, neurogenic bladder atony in adults and older children. dx and treatment of reflux esophagitis in adults, and used orally in infants and children for treatment of esophageal reflux

Question 9

carbachol (Miostat) - Direct-Acting

Answer 9

Eye drops. Induction of miosis to treat glaucoma

Question 10

cevimeline (Evoxac)- Direct-Acting

Answer 10

PO. Treatment of symptoms of dry mouth in Sjoegren’s

Question 11

pilocarpine (Salagen)- Direct- Acting

Answer 11

PO. Taken with meals. Treatment of symptoms of dry mouth in pts with Sjoegren’s.

Question 12

Direct-Acting Cholinergic Therapeutic Action

Answer 12

mimic effects of ACh and parasympathetic stimulation

Question 13

Effects of Direct-Acting Cholinergic Drugs

Answer 13

• slowed HR
• decreased myocardial contractility
• vasodilation
• bronchoconstriction
• increased bronchial mucus secretion
• increased GI activity and secretions
• increased bladder tone
• relaxation of GI and bladder sphincters
• pupil constriction

Question 14

Pharmokinetics of Direct-Acting Cholinergics

Answer 14

• short half-lives: 1-6 hrs
• absorbed well orally
• metabolism and excretion not known
• topical application not generally absorbed systemically

Question 15

Contraindications and Cautions with Direct-Acting Cholinergics

Answer 15

-used sparingly due to potential undesirable systemic effects
-use with caution in the presence of any condition that would be exacerbated by parasympathetic effects:
bradycardia
hypotension
vasodilation
coronary artery disease
epilepsy
Parkinson’s
peptic ulcer
intestinal or bladder obstruction
asthma
recent GI or bladder surgery

Question 16

Adverse effects of Cholinergics

Answer 16

CVS: bradycardia, heart block, hypotension, cardiac arrest
GI: N&V, cramps, diarrhea, increased salvation, involuntary defecation, difficulty swallowing and aspiration (r/t increased salvation), dehydration
GU: sense of urgency, sphincter relaxation
MISC: Flushing, increased diaphoresis

Question 17

Clinically important Drug-Drug Interactions with Direct-Acting Cholinergics

Answer 17

increased risk of cholinergic effects if drugs are combined with acetylcholinesterase inhibitors

Question 18

Indirect-Acting Cholinergics

Answer 18

drugs that react with acetylcholinesterase to prevent it from breaking down ACh in the synaptic cleft

Question 19

Cholinergic Crisis

Answer 19

presents with progressive muscle weakness and respiratory difficulty as accumulation of ACh at the cholinergic receptor site leads to reduced impulse transmission and muscle weakness.

Question 20

Ddonepezil (Aricept)- Prototype- Indirect-Acting Cholinergic

Answer 20

PO. Mgmt of Alzheimer’s dementia, including severe dementia

Question 21

galantamine (Razadyne)- Indirect-Acting Cholinergic

Answer 21

PO. Mgmt of mild to moderate Alzheimer’s dementia; delays progression of dz

Question 22

rivastigmine (Exelon)- Indirect-Acting Cholinergic

Answer 22

PO/Patch. Mgmt of mild to mod. Alzheimer’s dementia; treatment of dementia related to Parkinson dz

Question 23

tacrine (Cognex)- Indirect-Acting Cholinergic

Answer 23

PO. Mgmt of mild. to mod. Alzheimer’s dementia; withdrawn from market in 2012

Question 24

Indirect-Acting Cholinergic Therapeutic Action

Answer 24

reversibly block acetylcholinesterase at synaptic cleft, allows ACh to accumulate in cleft. More readily cross blood-brain barrier and seem to affect mostly cells in cortex

Question 25

Pharmokinetics of Indirect-Acting Cholinergics

Answer 25

• well absorbed orally
• distributed throughout body
• metabolism and excretion not known
• Alzheimer’s dz meds are metabolized in liver (longterm metabolism- 70hrs)
• half-life is 1-7 hrs

Question 26

Contraindications and Cautions with Indirect-Acting Cholinergics

Answer 26

• can induce labor and uterine contractions in pregnancy
• GI or GU obstructions
• bradycardia
• less likely to cause systemic parasympathetic effects, more localized than direct-acting, but caution should be exercised with conditions that could be exacerbated by cholinergic stimulation

Question 27

Adverse Effects of Indirect-Acting Cholinergics

Answer 27

• Same as Direct-Acting

- CNS: H/A, blurred vision, dizziness, drowsiness

Question 28

Pyridostigmine- Prototype- Indirect-Acting Cholinergic

Answer 28

PO/IM/IV. Treatment of myasthenia gravis, antidote for nondepolarizing neuromuscular junction blockers, increased survival after exposure to nerve gas